New ATLAS publication
June 30, 2021Collider Physics Group
“Measurement of the tttt production cross section in pp collisions at sqrt(s)=13 TeV with the ATLAS detector” has been submitted to JHEP. Members of the IFAE-ATLAS team (Aurelio Juste, Nicola Orlando, and Anil Sonay) have played a leading role in this publication, from designing the analysis strategy to the final multivariate technique and statistical analysis employed.
This paper presents a measurement of the four-top-quark production cross section in final states with a single lepton or an opposite-sign lepton pair in association with multiple jets using the full Run 2 dataset collected with the ATLAS detector. With four top quarks produced per event, this is a very rare Standard Model process with a predicted cross section of only 12 fb, and thus is very sensitive to beyond-the-SM (BSM) contributions. A sophisticated event categorization and multivariate technique is used to discriminate signal from background events. The result of this analysis is combined with a previous measurement in multilepton final states. The combined cross section is measured to be a factor of two higher than the SM prediction, although compatible with it within 2.0 standard deviations. The corresponding observed (expected) signal significance is .7 (2.6) standard deviations over the background-only prediction.
The IFAE team is currently working on an improved analysis targeting BSM production of four-top-quark events. Stay tuned!
More information on the ATLAS Physics Briefing
IFAE at EPS-HEP 2021
July 27, 2021
The European Physical Society conference on high energy physics 2021 (EPS-HEP 2021), one of the most important conferences in HEP of the year, is taking place online this week. Three IFAE groups are participating:
Phenomenology 2021 Symposium
May 26, 2021
Anil Sonay, member of the IFAE-ATLAS group at gave the talk “The search for rare top production and decay processes with the ATLAS experiment at the LHC” at Pheno 2021 on 24-26 May 2021